### Name: ablineclip
### Title: Add a straight line to a plot
### Aliases: ablineclip
### Keywords: aplot

### ** Examples

 x <- rnorm(100)
 y <- x + rnorm(100)
 lmfit <- lm(y~x)
 plot(x,y,xlim=c(-3.5,3.5))
 ablineclip(lmfit,x1=-2,x2=2,lty=2)
 ablineclip(h=0,x1=-2,x2=2,lty=3,col="red")
 ablineclip(v=0,y1=-2.5,y2=1.5,lty=4,col="green")



